php微信群发图文消息内容中图片不显示

Question

$art['articles'] = array();
$art['articles'][0]['thumb_media_id'] = I('mediaids');
$art['articles'][0]['author'] = '聚焦';
$art['articles'][0]['title'] = $imgs['title'];
$art['articles'][0]['content_source_url'] = str_replace(array('{website}','{imgid}'), array(C('website'),$imgs['id']), $imgs['url']);
$art['articles'][0]['content'] = preg_replace("/<([a-zA-Z]+)[^>]*>/","<\\1>",$imgs['content']);
$art['articles'][0]['digest'] = $imgs['description'];
$art['articles'][0]['show_cover_pic'] = $imgs['showpic'];
$med_info = $this->weixin->uploadArticles($art);